The broad objectives of the project focus on the unusual occurrence of multiple forms of glucose-6-phosphate (G6P) and 6-phosphogluconate (6PGA) dehydrogenases in Pseudomonas multiviorans, and are directed towards answering basic questions about (1) the roles of the enzymes in maintaining appropriate intracellular levels of NADH, NADPH, and other key metabolites, and (2) the importance of inhibition of the enzymes by ATP and NADPH. An unexpected finding of our earlier experiments was the simultaneous loss of normal G6P and 6PGA dehydrogenase species (there are 2 forms of each enzyme - one specific for NADP and the other active with NAD as well as NADP and subject to strong inhibition by ATP and NADPH) in mutant strains selected for failure to grow on glucose or characterized by slow growth on glucose and the appearance of high levels of a new ATP-insensitive G6P dehydrogenase in certain of the mutants. Our results tend to rule out obvious explanations for the loss of the 4 enzymes based on their being products of the same operon (their levels are not regulated coordinately) or their all sharing a common subunit (3 of the enzymes have been characterized with respect to subunit composition and antigenic properties, and the results are inconsistent with this possibility). A major goal of the projected research is to determine the basis for the apparent interdependence of formation of G6P dehydrogenase species. Certain of the mutant strains cited above exhibit a number of pleiotropic effects including overproduction of polyhydroxybutyrate, proliferation of membrane material and deficiency of inorganic pyrophosphatase (PPase) activity, which we propose are associated with loss of energy-linked regulation of G6P dehydrogenase and imbalance of NADPH formation relative to that of NADH. An important aim of the project is to examine the consequences of loss of energy-linked control over glucose catabolism and its apparent relationship with PPas deficiency in our mutant strains. As a corollary we hope to gain information about the physiological roles of PPase.